Alan Alda just announced that he has Parkinson's disease. Here's what that means.

In an interview Tuesday on CBS This Morning, 82-year-old actor Alan Alda opened up about a deeply personal life development: that he was diagnosed with Parkinson’s disease three years ago. “I asked for a scan because I thought I might have it,” he told CBS’s Anthony Mason on the show, before adding that it was a New York Timesarticle by Jane Brody that ignited his concern.

The article said that “if you act out your dreams, there’s a good chance that might be a very early symptom,” said Alda. “And by acting out your dreams I mean I was having a dream that someone was attacking me and I threw a sack of potatoes at them, but what I was really doing was throwing a pillow at my wife.”

Despite doctors’ reluctance to perform a scan of his brain (since he was showing no other symptoms), Alda persuaded them to take a closer look, ultimately leading to his diagnosis of Parkinson’s. Following the news, Alda says he began to develop more symptoms, including a tremor in his thumb.

But even though the diagnosis is a serious one, the M*A*S*H actor says it hasn’t slowed him down. “The thing I really want folks to know — and this is not to short-change people who are suffering with really severe symptoms; symptoms can get very bad and their families can suffer — but in the very beginning, to be immobilized by fear and think the worst thing has happened to you, it hasn’t happened to you,” Alda said on CBS. “You still have things you can do.”

Alda said he is now performing daily exercises that help alleviate some of the physical symptoms of the disease, exercises that include boxing and “marching to Sousa.”

According to the Mayo Clinic, Parkinson’s disease is defined as “a progressive nervous system disorder that affects movement.” It affects 10 million people worldwide. Discovered by scientist James Parkinson in 1817, it was originally called “shaking palsy.” In many ways, this shaking in the hands, fingers, or legs (called a tremor) is still the disease’s hallmark symptom, but it’s not the only one.

As Alda mentioned, one early symptom involves acting out dreams, while others include constipation, memory problems, late-onset depression, neck pain, muscle stiffness, and dizziness. The Mayo Clinic offers a picture of the disease’s early onset: “Your face may show little or no expression. Your arms may not swing when you walk. Your speech may become soft or slurred.”

Since the disease is degenerative, the symptoms continue to worsen over time. The mechanism behind this is a breakdown of nerve cells responsible for creating the feel-good chemical called dopamine. This deficiency in dopamine prompts degeneration of speech and movement, which happens over the course of more than a decade. But the good news is that the earlier the disease is diagnosed, the quicker doctors can work to limit the damage done to the brain.

In Alda’s case, on top of regular exercise, it’s likely he is taking one of the recommended medications for Parkinson’s. The majority of these work by introducing a chemical into the brain that the body converts into dopamine over time. Beyond that, there are drugs that are capable of lessening the effects of seizures and helping with other symptoms, such as cognitive decline. In extremely severe cases, deep brain stimulation can be carried out through surgery, usually in younger patients. Actor Michael J. Fox, who suffers from early-onset Parkinson’s, has had this treatment, which slows the progression of the disease.

Although it’s a serious diagnosis, it’s not a life-ending one. The disease itself is not fatal, which means that managing its progression is essential, and that’s something that Alda and his doctors seem to grasp.